Differential pressure and flow measurements have important applications in a wide range of fluid processes, including food and beverage production, water treatment, pharmaceuticals, hydrocarbon fuel extraction, petrochemical processing, manufacturing, transportation and energy production. In each of these applications, process measurement and control systems utilize a range of stand-alone pressure sensors, transmitters and field devices to monitor and control process pressure and related parameters, including mass and volumetric flow rates.
In many fluid processes, flow is not limited to a single component or phase. Examples include pulverized coal, coal slurry, hydraulic mining, oil/water/gas extraction and CO2-based flows for supercritical extraction or carbon sequestration. Where pressure-based measurements are used to determine the volumetric or mass flow rate, moreover, these measurements also depend upon fluid density. The density varies with process temperature and pressure, as well as the phase and composition of each individual flow component, and each of these factors plays a role in overall accuracy.